<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/vue-2.6.10.js"></script>
</head>
<body>
<div id="app">
    <input type="checkbox" value="Java" v-model="lan">Java<br>
    <input type="checkbox" value="Python" v-model="lan">Python<br>
    <input type="checkbox" value="Swift" v-model="lan">Swift<br>
    {{lan.join(",")}}
</div>
<script type="text/javascript">
    new Vue({
        el: "#app",
        data: {
            lan:[]
        },
    });
</script>
</body>
</html>